The acyl complex trans-[Pt(PPh3)2(COnBu)Cl] (A) has been synthesized by reaction of [Pt(PPh3)2Cl2] with 1-butene under 100 atm of CO at 80-100°C, in ethanol. With 2-butene rather than 1-butene under the same conditions, a mixt. of the above acyl complex and of trans-[Pt(PPh3)2(COsBu)Cl] (B) was formed. Complexes A and B do not interconvert. The new acyl complexes A and B have been characterized by IR and 1H NMR and 13C NMR spectroscopy. The ratio A/B increases with PPh3/Pt ratio and with temp. The formation of two isomers when 2-butene is used involves an isomerization process which is likely to be limited to the alkyl precursor complexes. The reactivity of complexes A and B has been tested in reactions with SnCl2, H2, HCl and trans-[Pt(PPh3)2HCl]. From the reaction solns. crystals of cis- [Pt(PPh3)2Cl(SnCl3)] have been obtained. Its mol. structure has been detd. by x-ray diffraction. The Pt atom has cis square planar coordination, with angular distortions due to steric factors. The strong trans influence of the SnCl3 group is confirmed by the lengthening of the trans Pt-P distance. The SnCl3 group has the pyramidal geometry found in all related compds.
Isolation and characterization of the acyl complexes trans-[Pt(PPh3)2(COR)Cl] (R = nBu or sBu) and their relevanceto the hydroformylation of linear butenes catalyzed by platinum/tin/triphenylphosphine catalytic systems. Molecularstructure of cis-[Pt(PPh3)2Cl(SnCl3)]
TONIOLO, Luigi;
1994-01-01
Abstract
The acyl complex trans-[Pt(PPh3)2(COnBu)Cl] (A) has been synthesized by reaction of [Pt(PPh3)2Cl2] with 1-butene under 100 atm of CO at 80-100°C, in ethanol. With 2-butene rather than 1-butene under the same conditions, a mixt. of the above acyl complex and of trans-[Pt(PPh3)2(COsBu)Cl] (B) was formed. Complexes A and B do not interconvert. The new acyl complexes A and B have been characterized by IR and 1H NMR and 13C NMR spectroscopy. The ratio A/B increases with PPh3/Pt ratio and with temp. The formation of two isomers when 2-butene is used involves an isomerization process which is likely to be limited to the alkyl precursor complexes. The reactivity of complexes A and B has been tested in reactions with SnCl2, H2, HCl and trans-[Pt(PPh3)2HCl]. From the reaction solns. crystals of cis- [Pt(PPh3)2Cl(SnCl3)] have been obtained. Its mol. structure has been detd. by x-ray diffraction. The Pt atom has cis square planar coordination, with angular distortions due to steric factors. The strong trans influence of the SnCl3 group is confirmed by the lengthening of the trans Pt-P distance. The SnCl3 group has the pyramidal geometry found in all related compds.
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